Hi, all. I've been brewing for a couple years now, almost all extract / steeping grains, with a couple of 1=gal all-grain batches thrown in. I want to move to full-size all greain (5 gal.) I have a standard 6.5 gal bottling bucket and I got a nylon mesh liner to use as a mash tun for the moment, before investing in a big cooler rig. My questin is, presuming a more-or-less standard 1.5 qts/ lb grain, allowing for room for mashing out, and a bit for safety, about how much grain should I be able to put in there? I understand I won't be making any 1.100 OG imperial stouts, but will I be able to mash for a nice pale ale, or belgian saison style? Any recipe hints from the experts here?
A 6.5 gallon mash tun will give you plenty of room. You can easily mash thicker than that and you don't need to do a mash out, which leaves you with more than enough room to play with. Assuming that you want to leave yourself about 1/2 a gallon of head room you can easily mash about 15 lbs of grain in that bucket at 1.25 qts/lb without a problem.
You may find that it's pretty hard to maintain your desired mash temp in a bucket. I haven't tried it, but the 2nd law of thermodynamics would seem to be against you here. But people have successfully mashed in them before, so good luck!
You're definitely gonna lose some heat, but it can be done. When I do my decoction mashes for example I'll pull my decoction into a 16 qt kettle, bring it up to sacc rest range, and then pull the kettle off the burner and wrap it in an old blanket for 20 min. Sure it loses a few degrees, but if you were to wrap your bucket in a blanket or sleeping bag I'm sure you can maintain a reasonable mash temp for 45 min or so. You could even mash in thick and then do a little boiling water infusion half way through to bump the temp up a little. Bottom line, it's not ideal but you can make it work.
I've found that a plastic bucket wrapped in some type of insulation material, blanket, sleeping bag, bubblewrap, etc. does a very nice job of holding temps within a degree or so for an hour or over. It also helps to have a piece of, cut to fit styrofoam to float on the top of the mash. If you use a probe thermometer you can just poke it through the foam to keep it in place.
I wrap my mash tun (ss pot) in about 12 (large and medium sized) bath towels, including 2 that are folded beneath the tun (that the tun sits on). During a 60 min mash the average temperature drops by about 4 F.
Just be sure to clean and sanitize well. The lacto on the grains and in the mash will want to infect your bottling bucket and tranfer to your beers during bottling.
My first mash tun was an old bottling bucket (keep a separate one for bottling, too great of an infection risk using the same one.) 5 gallon paint strainer bag, something underneath to prop it up (I used PVC), and any foam padding, blankets, etc for insulation. It won't hold temps like a cooler, but will hold them well enough. Its big enough for most 5 gallon batches too.
Thanks for the hints, everyone. I didn't really think about the potential for contamination for next bottling run, but I do wash everything well after each use and sanitize before using the next time, so I hope to be OK there. In reading the hints, I'll probable end up doing a slightly thicker mash, probably 1.25 qt/lb, so hopefully have the room for a bit of mashout, then be able to sparge more or less as normal. I'll let the initial temp be a degree or 2 higher, expecting to lose a bit over the course of the mash, though still wrapping in towels or blankets. I'll also pre-warm the bucket as I've read about other's doing with their metal or even cooler tuns. Hope to brew in a couple weeks, once that darn real live (TM) settles down a bit around here.
I haven't done this myself yet, but the guy that owns the homebrew store near me said it could be done with the bottling buckets and bubblewrap like geezer said above. I am personally not ready to spend such a long time on my brewing process so I still work with extracts, but eventually I will have the time to try it like you... Good luck!
